Linux memory probe

Dec 21, 2004 1 Replies

We have a couple of versions of Linux for a CPU we're using.



The later build gives us a problem we haven't sorted yet, so we are still selling and sending out the older one.



The older one doesn't find half the actual memory, the later one works fine. Sadly one of our customers is now short of memory space ( ain't it always the way )



Question is - does Linux expect something like Redboot to TELL it what physical memory map exists, or does the start-up code probe for it?



I know that the BIOS on a PC used to do this so Windoze/DOS wasn't poking around in it's own memory, but I have no idea where the responsibility lies under Linux.



Basically I'm trying to work out if there is a source file in the new linux build we can nick, and put into the previous build, to make the other memory magically available.



David Collier



email can be sent to Dexdyne.com , under name from_usenet@


It would be easier to give specific instructions if you told the kernel versions in question and the target hardware architecture.

The memory probe is in the architecture-dependent source directory, file setup.S.

If the sources are in the usual place (/usr/src/linux), the setup file for i386 PC architecture is in /usr/src/linux/arch/i386/boot/setup.S.

For 2.4.27 kernel sources, have a look at code starting at the label meme820:

HTH

Tauno Voipio tauno voipio (at) iki fi

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